Force and torque sensors having six degrees of freedom (6 DOF) are used for robot control in most applications involving an interaction between a tool and a work object. Applications of such tools can include assembling, grinding, deburring, drilling, milling, machine tending, laser welding, sheet bending, mechanical testing, etc.
Moreover, in many cases, the designing of programs for such applications is difficult using known methods even though 6 DOF force/torque sensors are used to make direct interaction between human beings and robots possible during calibration, programming and program editing.
Accordingly, known techniques do not provide a means to develop, manufacture and assemble a 6 DOF force/torque sensor efficiently and cost-effectively.
WO 9904235 A discloses a load cell body for transmitting forces and moments in plural directions. The load cell body includes an integral assembly having: a rigid central hub; a rigid annular ring concentric with the central hub; at least three radial tubes extending radially along corresponding longitudinal axes from the central hub to the annular ring; and a flexure member extending between an end of each radial tube to the annular ring. The flexure member is compliant for displacements of each corresponding radial tube along the corresponding longitudinal axis.
This known multiaxial force sensor is highly accurate, but it needs a large amount of handwork in manufacturing. This causes high cost and limits the achievable production volume.
The application of strain gauges via adhesive bonding needs much care, as they have to be applied to varying sides of complex 3-dimensional metal structures. The precision of the resulting measurement depends considerably on the accurate orientation of the strain gauges, and even with mounting aids, the handmade assembly is a slow and moderately precise process causing significant efforts.
Based on this state of the art it is an object of the disclosure to provide for multiaxial force and/or torque sensors in a definite arrangement in particular for use for robot control and a method for assembling the respective sensors which is less expensive than with the state of the art, since multiaxial force-torque sensors made with state-of-the art strain gauge technology are high-precision, but complex and very expensive products since the typical design requires a large amount of handwork in production.